U.S. patent application number 13/887263 was filed with the patent office on 2013-09-19 for multilayer ceramic electronic component.
This patent application is currently assigned to SAMSUNG ELECTRO-MECHANICS CO., LTD.. The applicant listed for this patent is SAMSUNG ELECTRO-MECHANICS CO., LTD.. Invention is credited to Jong Hoon BAE, Sung Hyuk CHOI, Jun Hee KIM, Sang Huk KIM, Jang Ho LEE, Seon Ki SONG, Ju Myung SUH.
Application Number | 20130242459 13/887263 |
Document ID | / |
Family ID | 47575714 |
Filed Date | 2013-09-19 |
United States Patent
Application |
20130242459 |
Kind Code |
A1 |
KIM; Sang Huk ; et
al. |
September 19, 2013 |
MULTILAYER CERAMIC ELECTRONIC COMPONENT
Abstract
There is provided a multilayer ceramic electronic component,
including: a ceramic body including a dielectric layer having an
average thickness of 0.6 .mu.m or less; and first and second inner
electrode layers within the ceramic body, disposed to face each
other with the dielectric layer interposed therebetween, wherein
the dielectric layer includes contact dielectric grains in contact
with the first or second inner electrode layer and non-contact
dielectric grains not in contact with the first or second inner
electrode layer, and, when an average thickness of the dielectric
layer is defined as td and an average diameter of the contact
dielectric grains is defined as De, De/td.ltoreq.0.35 is satisfied.
The multilayer ceramic electronic component has improved continuity
of the inner electrode layer, large capacitance, extended
accelerated lifespan and excellent reliability.
Inventors: |
KIM; Sang Huk; (Suwon,
KR) ; LEE; Jang Ho; (Suwon, KR) ; SUH; Ju
Myung; (Anyang, KR) ; CHOI; Sung Hyuk; (Suwon,
KR) ; BAE; Jong Hoon; (Anyang, KR) ; KIM; Jun
Hee; (Hwaseong, KR) ; SONG; Seon Ki; (Anyang,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SAMSUNG ELECTRO-MECHANICS CO., LTD. |
Suwon |
|
KR |
|
|
Assignee: |
SAMSUNG ELECTRO-MECHANICS CO.,
LTD.
Suwon
KR
|
Family ID: |
47575714 |
Appl. No.: |
13/887263 |
Filed: |
May 3, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13478900 |
May 23, 2012 |
8437115 |
|
|
13887263 |
|
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Current U.S.
Class: |
361/301.4 |
Current CPC
Class: |
H01G 4/012 20130101;
H01G 4/1209 20130101; H01G 4/30 20130101 |
Class at
Publication: |
361/301.4 |
International
Class: |
H01G 4/30 20060101
H01G004/30 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 28, 2011 |
KR |
10-2011-0075084 |
Claims
1-18. (canceled)
19. A multilayer ceramic electronic component, comprising: a
ceramic body including a dielectric layer having an average
thickness of 0.6 .mu.m or less; and first and second inner
electrode layers within the ceramic body, disposed to face each
other with the dielectric layer interposed therebetween, wherein
the dielectric layer includes contact dielectric grains in contact
with the first or second inner electrode layer and non-contact
dielectric grains not in contact with the first or second inner
electrode layer, when an average thickness of the dielectric layer
is defined as td and an average diameter of the contact dielectric
grains is defined as De, De/td.ltoreq.0.35 is satisfied, and when
an average diameter of the non-contact dielectric grains is defined
as Dc, Dc/td.ltoreq.0.25 is satisfied.
20. The multilayer ceramic electronic component of claim 19,
wherein, when an average diameter of ceramic powder particles added
to the first and second inner electrode layers is defined as Di and
an average diameter of ceramic powder particles used in the
dielectric layer is defined as Dd, 0.1<Di/Dd.ltoreq.1 is
satisfied.
21. The multilayer ceramic electronic component of claim 19,
wherein ceramic powder added to the first and second inner
electrode layers and ceramic powder used in the dielectric layer
have the same composition.
22. The multilayer ceramic electronic component of claim 19,
wherein the first or second inner electrode layer has a continuity
of 80% or more.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the priority of Korean Patent
Application No. 10-2011-0075084 filed on Jul. 28, 2011, in the
Korean Intellectual Property Office, the disclosure of which is
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a multilayer ceramic
electronic component, and more particularly, to a large-capacity
multilayer ceramic electronic component having excellent
reliability.
[0004] 2. Description of the Related Art
[0005] In accordance with the recent trend toward miniaturization
of electronic products, the demand for multilayer ceramic
electronic components having a small size and large capacitance has
been also increased.
[0006] Therefore, dielectric layers and inner electrode layers have
been thinned and increasingly multilayered by various methods.
Recently, as the dielectric layers have been thinned, multilayer
ceramic electronic components having an increased number of
lamination layers have been manufactured.
[0007] As the dielectric layers and the inner electrode layers are
thinned in order to realize larger capacitances, the thicknesses of
the inner electrode layers may neither be uniform nor continuously
maintained, and thus, the inner electrode layers may be partially
disconnected, thereby causing a break in the connectivity
thereof.
[0008] Furthermore, as the inner electrode layers are disconnected,
the dielectric layers are partially thickened or thinned although
the dielectric layers have a uniform average thickness. Insulating
properties in portions in which the dielectric layers are thinned
may be deteriorated, resulting in a deterioration of
reliability.
[0009] Meanwhile, fine-grain ceramic powders contained in an inner
electrode paste leak into the dielectric layer during a sintering
process, thereby causing abnormal grain growth of dielectric grains
in contact with the inner electrode layers. This may result in a
deterioration of the reliability of the multilayer ceramic
electronic component.
SUMMARY OF THE INVENTION
[0010] An aspect of the present invention provides a large-capacity
multilayer ceramic electronic component having excellent
reliability.
[0011] According to an aspect of the present invention, there is
provided a multilayer ceramic electronic component, including: a
ceramic body including a dielectric layer having an average
thickness of 0.6 .mu.m or less; and first and second inner
electrode layers within the ceramic body, disposed to face each
other with the dielectric layer interposed therebetween, wherein
the dielectric layer includes contact dielectric grains in contact
with the first or second inner electrode layer and non-contact
dielectric grains not in contact with the first or second inner
electrode layer, and when an average thickness of the dielectric
layer is defined as td and an average diameter of the contact
dielectric grains is defined as De, De/td.ltoreq.0.35 is
satisfied.
[0012] When an average diameter of the non-contact dielectric
grains is defined as Dc, Dc/td.ltoreq.0.25 may be satisfied
[0013] When an average diameter of ceramic powder particles added
to the first and second inner electrode layers is defined as Di and
an average diameter of ceramic powder particles used in the
dielectric layer is defined as Dd, 0.1<Di/Dd<1 may be
satisfied.
[0014] Ceramic powder added to the first and second inner electrode
layers and ceramic powder used in the dielectric layer may have the
same composition.
[0015] The first or second inner electrode layer may have a
continuity of 80% or more.
[0016] According to another aspect of the present invention, there
is provided a multilayer ceramic electronic component, including: a
ceramic body including a dielectric layer having an average
thickness of 0.6 .mu.m or less; and first and second inner
electrode layers formed within the ceramic body, each having a
continuity of 80% or more, wherein the dielectric layer includes
contact dielectric grains in contact with the first or second inner
electrode layer and non-contact dielectric grains not in contact
with the first or second inner electrode layer, and, when an
average thickness of the dielectric layer is defined as td and an
average diameter of the contact dielectric grains is defined as De,
De/td.ltoreq.0.35 is satisfied.
[0017] According to another aspect of the present invention, there
is provided a multilayer ceramic electronic component, including: a
ceramic body including a plurality of dielectric layers laminated
therein and having an average thickness of 0.6 .mu.m or less; and a
plurality of first and second inner electrode layers formed within
the ceramic body, wherein the dielectric layer includes contact
dielectric grains in contact with the first or second inner
electrode layer and non-contact dielectric grains not in contact
with the first or second inner electrode layer, and when an average
thickness of the dielectric layer is defined as td and an average
diameter of the contact dielectric grains is defined as De,
De/td.ltoreq.0.35 is satisfied.
[0018] According to another aspect of the present invention, there
is provided a multilayer ceramic electronic component, including: a
ceramic body including a plurality of dielectric layers laminated
therein and having an average thickness of 0.6 .mu.m or less; and a
plurality of first and second inner electrode layers formed within
the ceramic body, each having a continuity of 80% or more, wherein
the dielectric layer includes contact dielectric grains in contact
with the first or second inner electrode layer and non-contact
dielectric grains not in contact with the first or second inner
electrode layer, and, when an average thickness of the dielectric
layer is defined as td and an average diameter of the contact
dielectric grains is defined as De, De/td.ltoreq.0.35 is
satisfied.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The above and other aspects, features and other advantages
of the present invention will be more clearly understood from the
following detailed description taken in conjunction with the
accompanying drawings, in which:
[0020] FIG. 1 is a perspective view schematically showing a
multilayer ceramic capacitor according to an embodiment of the
present invention;
[0021] FIG. 2 shows a cross-sectional view taken along line B-B' of
FIG. 1 and an enlarged view showing continuity of an inner
electrode layer; and
[0022] FIG. 3 shows a cross-sectional view taken along line B-B' of
FIG. 1 and an enlarged view showing contact dielectric grains and
noncontact dielectric grains.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0023] Embodiments of the present invention will now be described
in detail with reference to the accompanying drawings. The
invention may, however, be embodied in many different forms and
should not be construed as being limited to the embodiments set
forth herein. Rather, these embodiments are provided so that this
disclosure will be thorough and complete, and will fully convey the
scope of the invention to those skilled in the art. In the
drawings, the shapes and dimensions of components may be
exaggerated for clarity, and the same reference numerals will be
used throughout to designate the same or like components.
[0024] FIG. 1 is a perspective view schematically showing a
multilayer ceramic capacitor according to an embodiment of the
present invention.
[0025] FIG. 2 is a cross-sectional view taken along line B-B' of
FIG. 1 and an enlarged view showing continuity of an inner
electrode layer.
[0026] FIG. 3 is a cross-sectional view of FIG. 1 taken along line
B-B' and an enlarged view showing contact dielectric grains and
noncontact dielectric grains.
[0027] Referring to FIGS. 1 through 3, a multilayer ceramic
electronic component according to an embodiment of the present
invention may include: a ceramic body 10 including a dielectric
layer 1 having an average thickness of 0.6 .mu.m or less; and first
and second inner electrode layers 21 and 22 disposed to face each
other with the dielectric layer 1 interposed therebetween within
the ceramic body 10. The dielectric layer 1 may include contact
dielectric grains in contact with the first or second inner
electrode layer 21 or 22 and non-contact dielectric grains not in
contact with the first or second inner electrode layer 21 or 22.
When an average thickness of the dielectric layer 1 is defined as
td and an average diameter of the contact dielectric grains is
defined as De, De/td.ltoreq.0.35 may be satisfied.
[0028] Meanwhile, a multilayer ceramic electronic component
according to another embodiment of the present invention may
include: a ceramic body 10 including a dielectric layer 1 having an
average thickness of 0.6 .mu.m or less; and first and second inner
electrode layers 21 and 22 formed within the ceramic body 10, each
having a continuity of 80% or more. The dielectric layer 1 may
include contact dielectric grains in contact with the first or
second inner electrode layer 21 or 22 and non-contact dielectric
grains not in contact with the first or second inner electrode
layer 21 or 22. When an average thickness of the dielectric layer 1
is defined as td and an average diameter of the contact dielectric
grains is defined as De, De/td.ltoreq.0.35 may be satisfied.
[0029] The first and second inner electrode layers 21 and 22 may be
formed by using a conductive paste made of at least one of, for
example, precious metal materials, such as palladium (Pd),
palladium-silver (Pd--Ag) alloy and the like, nickel (Ni), and
copper (Cu), but not particularly limited thereto.
[0030] Outer electrodes 3 may be formed outside the ceramic body 10
in order to form capacitance, and may be electrically connected
with the first and second inner electrode layers 21 and 22.
[0031] The outer electrodes 3 may be formed of the same conductive
material as that of the inner electrode layers, but not limited
thereto. For example, copper (Cu), silver (Ag), nickel (Ni), or the
like may be used for the outer electrodes 3.
[0032] The outer electrode 3 may be formed by coating a conductive
paste prepared by adding glass frit in a metal powder, and then
performing a sintering process.
[0033] According to the embodiment of the present invention, the
average thickness of the dielectric layer 1 may be 0.6 .mu.m or
less.
[0034] In the embodiment of the present invention, the thickness of
the dielectric layer 1 may refer to an average thickness of the
dielectric layer 1 disposed between the inner electrode layers 21
and 22.
[0035] The average thickness of the dielectric layer 1 may be
measured by scanning a cross section in a length direction of the
ceramic body 10, using a scanning electron microscope (SEM), as
shown in FIG. 2.
[0036] For example, as shown FIG. 2, the average thickness of the
dielectric layer 1 may be obtained by measuring thickness at 30
equidistant points in a length direction, in any one dielectric
layer extracted from an image obtained by scanning a cross section
in a length-thickness (L-T) direction, which is cut in a central
part in a width (W) direction of the ceramic body 10, using a
scanning electron microscope (SEM), and then calculating an average
thickness value.
[0037] The thickness at 30 equidistant points may be measured in a
capacitance forming part, referring to an area in which the first
and second inner electrode layers 21 and 22 overlap each other.
[0038] In addition, when this measurement process is extensively
performed on ten or more dielectric layers and average values
thereofare measured, the average thickness of the dielectric layer
may be more generalized.
[0039] The thickness of the inner electrode layer 21 or 22 after
sintering is not particularly limited so long as it can form
capacitance. For example, the thickness of the inner electrode
layer may be 1 .mu.m or less.
[0040] Referring to FIG. 2, the multilayer ceramic electronic
component according to the embodiment of the present invention may
include a ceramic body 10 including a dielectric layer 1 having an
average thickness of 0.6 .mu.m or less; and first and second inner
electrode layers 21 and 22 formed within the ceramic body 10, each
having a continuity of 80% or more.
[0041] The continuity of the inner electrode layer may be defined
as a ratio of an actual total length of electrode portions, to an
ideal total length of the first or second inner electrode layer 21
or 22.
[0042] For example, the continuity of the inner electrode layer may
be measured from an image obtained by scanning a cross section in a
length direction of the ceramic body 10 using a scanning electron
microscope (SEM), as shown in FIG. 2.
[0043] Specifically, as shown in FIG. 2, the continuity of the
inner electrode layer may be obtained by measuring the actual total
length of the electrode portions of the inner electrode layer based
on the ideal total length of the inner electrode layer, in any one
inner electrode layer extracted from an image obtained by scanning
a cross section in a length-thickness (L-T) direction, which is cut
in a central part in a width (W) direction of the ceramic body 10,
using a scanning electron microscope (SEM).
[0044] The continuity of the inner electrode layer may be measured
in a capacitance forming part, referring to an area in which the
first and second inner electrode layers 21 and 22 overlap each
other.
[0045] In addition, when this measurement process for obtaining the
continuity of the inner electrode layer is extensively performed on
ten or more inner electrode layers in a central part of the cross
section in the length-thickness (L-T) direction and average values
thereof are calculated, the continuity of the inner electrode layer
may be more generalized.
[0046] Specifically, as shown in FIG. 2, when the ideal total
length of the first or second inner electrode layer 21 or 22 in any
one part thereof is defined as A and actual total lengths of the
electrode portions are defined as c1, c2, c3, . . . , and cn, the
continuity of the inner electrode layer may be expressed by
(c1+c2+c3++cn)/A.
[0047] In FIG. 2, although the electrode portions are expressed by
c1, c2, c3 and c4, the number of the electrode portions is not
particularly limited.
[0048] In addition, the continuity of the inner electrode layer may
refer to a coverage ratio of the inner electrode layer, and may be
defined as a ratio of an actual total area of the electrode
portions to the ideal total area of the inner electrode layer.
[0049] The continuity (c1+c2+c3+c4/A) of the inner electrode layer
21 or 22 may be variously embodied according to a method to be
described below. In the multilayer ceramic electronic component
according to the embodiment of the present invention, the
continuity (c1+c2+c3+c4/A) of the inner electrode layer 21 or 22
may be 80% or more.
[0050] In addition, disconnection portions 4 of the inner electrode
layer 21 or 22 may be pores or ceramics.
[0051] In order to realize the continuity (c1+c2+c3+c4/A) of the
inner electrode layer 21 or 22 to be 80% or more, the size of metal
powder particles in the conductive paste for forming the inner
electrode layer may be varied or the amount of an organic material
or ceramic material may be controlled.
[0052] In addition, a temperature rise rate and a sintering
atmosphere may be adjusted during a sintering process to thereby
control the continuity of the inner electrode layer.
[0053] According to the embodiment of the present invention, in
order to realize the continuity of the inner electrode layer, a
method of controlling the size and amount of ceramic particles
added to the conductive paste may be used.
[0054] Specifically, the ceramic material added in the conductive
paste is identical to the ceramic material used in the dielectric
layer, but not particularly limited thereto. For example, the
ceramic material may be a barium titanate (BaTiO.sub.3) powder.
[0055] Here, the average diameter Di of the ceramic particles may
be commonly known in the art, but is not particularly limited.
However, it may be determined in order to control an average
diameter of contact dielectric grains in contact with the inner
electrode layer 21 or 22.
[0056] According to the embodiment of the present invention, the
continuity (c1+c2+c3+c4/A) of the inner electrode layer 21 or 22 is
realized as 80% or more, whereby a multilayer ceramic capacitor
having increased capacitance and excellent reliability may be
manufactured.
[0057] Referring to FIG. 3, in the multilayer ceramic electronic
component according to the embodiment of the present invention, the
average thickness td of the dielectric layer 1 after sintering may
be 0.6 .mu.m or less.
[0058] In addition, the dielectric layer 1 may include contact
dielectric grains in contact with the first or second inner
electrode layer 21 or 22 and non-contact dielectric grains not in
contact with the first or second inner electrode layer 21 or 22.
When an average diameter of the contact dielectric grains is
defined as De, De/td.ltoreq.0.35 may be satisfied.
[0059] In this embodiment, the average diameter De of the contact
dielectric grains may be measured by analyzing an image of a cross
section of the dielectric layer extracted by a scanning electron
microscope (SEM). For example, an average grain size of the
dielectric layer may be measured by using a grain size measurement
software supporting an average grain size measurement method
defined by American Society for Testing and Materials (ASTM)
E112.
[0060] The average diameter De of the contact dielectric grains may
be adjusted by controlling an average diameter of ceramic powder
particles used in the forming of the dielectric layer 1 and an
average diameter of ceramic powder particles added to the
conductive paste for forming the first and second inner electrode
layers 21 and 22.
[0061] The average diameter of the ceramic powder particles used in
the forming of the dielectric layer 1 is not particularly limited,
and may be controlled so as to attain the objects of the present
invention. For example, the average diameter of the ceramic powder
particles may be 300 nm or less.
[0062] In a case in which a ratio (De/td) of the average diameter
De of the contact dielectric grains to the average thickness td of
0.6 .mu.m or less of the dielectric layer 1 is 0.35 or less, a
high-capacity multilayer ceramic capacitor having excellent
reliability may be realized.
[0063] In a case in which a ratio (De/td) of the average diameter
De of the contact dielectric grains to the average thickness td of
the dielectric layer 1 is above 0.35, the reliability of the
multilayer ceramic electronic component in which such a thin-film
dielectric layer is employed may be deteriorated since the average
diameter of the contact dielectric grains is large.
[0064] In addition, when an average diameter of the non-contact
dielectric grains is defined as Dc, Dc/td.ltoreq.0.25 may be
satisfied.
[0065] The average diameter Dc of the non-contact dielectric grains
may be measured by analyzing an image of a cross section of the
dielectric layers, as shown in FIG. 3, which is cut in a laminating
direction of the dielectric layers and scanned by a scanning
electron microscope (SEM). For example, an average grain size of
the dielectric layer may be measured by using a grain size
measurement software supporting an average grain size measurement
method defined by American Society for Testing and Materials (ASTM)
E112.
[0066] Specifically, in a case in which a ratio (Dc/td) of the
average diameter Dc of the non-contact dielectric grains to the
average thickness td of 0.6 .mu.m or less of the dielectric layer 1
is 0.25 or less, a high-capacity multilayer ceramic capacitor
having excellent reliability may be realized.
[0067] The average diameter Dc of the non-contact dielectric grains
may be also adjusted by controlling the average diameter of ceramic
powder particles used in the forming of the dielectric layer 1, so
as to attain the objects of the present invention.
[0068] Also, in a case in which a ratio (Dc/td) of the average
diameter Dc of the non-contact dielectric grains to the average
thickness td of the dielectric layer 1 is above 0.25, the
reliability of the multilayer ceramic electronic component
according to the embodiment of the present invention may be
deteriorated since the average diameter of the non-contact
dielectric grains is large.
[0069] According to the embodiment of the present invention, a raw
material for forming the dielectric layer 1 is not particularly
limited as long as sufficient capacitance can be obtained. For
example, the raw material may be a barium titanate (BaTiO.sub.3)
powder.
[0070] As a material for forming the dielectric layer 1, various
ceramic additives, organic solvents, plasticizers, binders,
dispersants, or the like may be added to a powder such as the
barium titanate (BaTiO.sub.3) powder.
[0071] According to the embodiment of the present invention, a
high-capacity multilayer ceramic capacitor having excellent
reliability can be realized when the average thickness td of the
dielectric layer 1 is 0.6 .mu.m or less, the continuity
(c1+c2+c3+c4 cn/A) of the first or second inner electrode layer 21
or 22 is 80% or more, the ratio (De/td) of the average diameter of
the contact dielectric grains to the average thickness of the
dielectric layer 1 is 0.35 or less, and the ratio (Dc/td) of the
average diameter of the non-contact dielectric grains to the
average thickness of the dielectric layer 1 is 0.25 or less.
[0072] Meanwhile, when an average diameter of ceramic powder
particles added to the inner electrode layer is defined as Di and
an average diameter of ceramic powder particles used in the
dielectric layer is defined as Dd, 0.1<Di/Dd<1 may be
satisfied.
[0073] In a case in which Di/Dd is 0.1 or less, a difference
between the average diameter of ceramic powder particles added to
the inner electrode layer and the average diameter of ceramic
powder particles used in the dielectric layer is so large that
sintering shrinkage of the inner electrode layer is not effectively
suppressed, thereby causing problems in the forming of capacitance
due to a deterioration of electrode continuity. In addition, since
the inner electrode layer is thickened at ends of each
disconnection portion, a distance between adjacent inner electrode
layers is shortened, resulting in a lowering of breakdown voltage,
whereby reliability is deteriorated.
[0074] Furthermore, in a case in which Di/Dd is above 1, since the
average diameter of ceramic powder particles added to the inner
electrode layer is larger than the average diameter of ceramic
powder particles used in the dielectric layer, sintering shrinkage
of the inner electrode layer is not effectively suppressed, and the
ceramic powder particles added to the inner electrode layer leak
into the dielectric layer during a sintering procedure such that
the thickness of the dielectric layer may be excessively increased,
thereby causing problems in the forming of capacitance and
reliability.
[0075] A high-capacity multilayer ceramic electronic component
having excellent reliability can be realized when the average
diameter Di of ceramic powder particles added to the inner
electrode layer and the average diameter Dd of ceramic powder
particles used in the dielectric layer satisfy
0.1<Di/Dd<1.
[0076] In addition, a composition of the ceramic powder used in the
dielectric layer and that of the ceramic powder added to the inner
electrode layer are not particularly limited; however, when they
are identical to each other, reliability may be improved.
[0077] Meanwhile, a multilayer ceramic electronic component
according to another embodiment of the present invention may
include: a ceramic body 10 including a plurality of dielectric
layers 1 laminated therein and having an average thickness of 0.6
.mu.m or less; and a plurality of first and second inner electrode
layers 21 and 22 formed within the ceramic body 10. The dielectric
layers 1 may include contact dielectric grains in contact with the
first or second inner electrode layer 21 or 22 and non-contact
dielectric grains not in contact with the first or second inner
electrode layer 21 or 22. When the average thickness of the
dielectric layers 1 is defined as td and an average diameter of the
contact dielectric grains is defined as De, De/td.ltoreq.0.35 may
be satisfied.
[0078] Meanwhile, a multilayer ceramic electronic component
according to another embodiment of the present invention may
include: a ceramic body 10 including a plurality of dielectric
layers 1 laminated therein and having an average thickness of 0.6
.mu.m or less; and a plurality of first and second inner electrode
layers 21 and 22 formed within the ceramic body 10, each having a
continuity of 80% or more. The dielectric layers 1 may include
contact dielectric grains in contact with the first or second inner
electrode layer 21 or 22 and non-contact dielectric grains not in
contact with the first or second inner electrode layer 21 or 22.
When the average thickness of the dielectric layers 1 is defined as
td and an average diameter of the contact dielectric grains is
defined as De, De/td.ltoreq.0.35 may be satisfied.
[0079] Since the multilayer ceramic electronic component according
to this embodiment is substantially identical to the multilayer
ceramic electronic component according to the previous embodiment
except that the dielectric layers and the first and second inner
electrode layers are laminated in plural, descriptions overlapping
each other will be omitted.
[0080] Hereafter, the present invention will be described in detail
with reference to examples, but is not limited thereto.
[0081] Tests were performed in order to determine the degree of
continuity of the first or second inner electrode layer 21 or 22
according to the amount of barium titanate inputted therein, and
improvement in reliability according to various average diameters
of contact dielectric grains and non-contact dielectric grains, in
multilayer ceramic capacitors in which dielectric layers 1 having
an average thickness of 0.6 .mu.m or less are provided.
[0082] Each multilayer ceramic capacitor was manufactured as
follows.
[0083] First, a slurry including a powder, such as barium titanate
(BaTiO.sub.3) or the like, was coated on a carrier film and dried
to prepare a plurality of ceramic green sheets having a thickness
of 1.05 .mu.m or 0.95 .mu.m, thereby forming dielectric layers
1.
[0084] Then, a conductive paste for inner electrode layers was
prepared. Here, an average diameter of barium titanate powder
particles added to the inner electrode layers was controlled such
that an average size of nickel particles was 0.05 .mu.m to 0.2
.mu.m, and 0.1<Di/Dd<1 was satisfied. The amount of barium
titanate powder was varied by 5 to 10% based on the weight of
nickel.
[0085] The conductive paste for inner electrode layers was coated
on the green sheets by a screen printing method to thereby form
inner electrode layers, and then the resulting structures were then
laminated in amounts of 200 to 250 layers to manufacture a
laminate.
[0086] Laminate compressing and cutting processes were subsequently
performed to manufacture a chip having a 0603 standard size, and
the chip was sintered at a temperature of 1050.quadrature. to
1200.quadrature. under a reduction atmosphere of H.sub.2 of 0.1% or
less.
[0087] Then, an outer electrode forming process, a plating process,
and the like were performed to manufacture a multilayer ceramic
capacitor.
[0088] Multilayer ceramic capacitor samples were variously
manufactured according to the average thickness of the dielectric
layers 1. As a result of observing cross sections of the multilayer
ceramic capacitors, the average thickness of the inner electrode
layers was 0.4 .mu.m to 0.9 .mu.m and the average thickness of the
dielectric layers was 0.5 .mu.M to 0.8 .mu.M.
[0089] In addition, the continuity of the inner electrode layers
was determined by measuring continuity in a capacitance forming
part of 10 inner electrode layers in a central part of a cross
section in a length-thickness (L-T) direction, which is cut in a
central part in a width (W) direction of the laminate ceramic body
10. In order to determine the degree of the continuity of the inner
electrode layer, a ratio of the actual total length of the
electrode portions to the ideal total length of the inner electrode
layer was measured from an image obtained by scanning a cross
section of the 10 inner electrode layers using a scanning electron
microscope (SEM).
[0090] Table 1 below shows the continuity of the inner electrode
layer according to the input ratio of barium titanate (BaTiO.sub.3)
powders inputted into the inner electrode layer, and
high-temperature accelerated lifespan according to the thickness of
the dielectric layers and average diameters of contact dielectric
grains and non-contact dielectric grains.
TABLE-US-00001 TABLE 1 Average Average Ceramic BaTiO.sub.3
Thickness Average Average Diameter of Thickness of Powder Size
Content in Continuity of Diameter of Diameter of NG rate In
Dielectric Dielectric in Inner Inner of Inner Dielectric Contact
Non-contact High- Powder Green Electrode Electrode Electrode Layer
Dielectric Dielectric temperature Sample (D.sub.d) Sheet Layer
Paste Layer Paste Layer t.sub.d Grain Grain Accelerated No. (nm)
(.mu.m) (D.sub.i) (nm) (%) (B/A) (.mu.m) D.sub.e (.mu.m) D.sub.c
(.mu.m) D.sub.e/t.sub.d D.sub.c/t.sub.d Lifespan 1 100 1.05 20 15.0
0.94 0.62 0.230 0.142 0.37 0.23 0/200 2 120 1.05 20 7.5 0.80 0.61
0.210 0.165 0.34 0.27 0/200 *3 100 1.05 10 7.5 0.65 0.60 0.225
0.138 0.38 0.23 4/200 *4 120 1.05 50 7.5 0.81 0.59 0.205 0.155 0.35
0.26 1/200 *5 100 1.05 20 5.0 0.78 0.58 0.163 0.142 0.28 0.24 2/200
*6 100 0.95 20 15.0 0.95 0.57 0.228 0.139 0.40 0.24 2/200 *7 100
0.95 50 5.0 0.72 0.53 0.160 0.132 0.30 0.25 3/200 *8 100 0.95 20
5.0 0.77 0.52 0.158 0.130 0.30 0.25 3/200
[0091] Referring to Table 1, Samples 1 and 2 each had dielectric
layers with an average thickness of above 0.6 .mu.m. In these
cases, good results are shown in a high-temperature accelerated
lifespan test even in the case that a ratio (De/td) of the average
diameter of contact dielectric grains to the average thickness of
the dielectric layers 1 and a ratio (Dc/td) of the average diameter
of non-contact dielectric grains to the average thickness of the
dielectric layers 1 deviate from a numerical value range of the
present invention.
[0092] On the other hand, Samples 3 to 8 each had dielectric layers
with an average thickness of 0.6 .mu.m or less. In these cases,
problems may occur in a high-temperature accelerated lifespan test
and a reliability test if the continuity of the inner electrode
layer, the ratio (De/td) of the average diameter of contact
dielectric grains to the average thickness of the dielectric layers
1, and the ratio (Dc/td) of the average diameter of non-contact
dielectric grains to the average thickness of the dielectric layers
1 deviate from a numerical value range of the present
invention.
[0093] Therefore, it could be seen that the multilayer ceramic
electronic component according to an embodiment of the present
invention has improved effects in high-temperature accelerated
lifespan and reliability when the average thickness td of the
dielectric layers 1 is 0.6 .mu.m or less after sintering.
[0094] Table 2 below shows the continuity of the inner electrode
layer according to the input ratio of barium titanate (BaTiO.sub.3)
powders inputted in the inner electrode layer, and high-temperature
accelerated lifespan according to the average diameters of contact
dielectric grains and non-contact dielectric grains, in a case in
which the average thickness td of the dielectric layers is 0.6
.mu.m or less.
TABLE-US-00002 TABLE 2 Average Average Ceramic BaTiO.sub.3
Thickness Average Average Diameter of Thickness of Powder Size
Content in Continuity of Diameter of Diameter of NG rate In
Dielectric Dielectric in Inner Inner of Inner Dielectric Contact
Non-contact High- Powder Green Electrode electrode Electrode Layer
Dielectric Dielectric temperature Sample (D.sub.d) Sheet Layer
Paste Layer Paste Layer t.sub.d Grain Grain Accelerated No. (nm)
(.mu.m) (D.sub.i) (nm) (%) (B/A) (.mu.m) D.sub.e (.mu.m) D.sub.c
(.mu.m) D.sub.e/t.sub.d D.sub.c/t.sub.d Lifespan *9 100 1.05 10
10.0 0.70 0.59 0.235 0.142 0.40 0.24 3/200 *10 100 1.05 10 7.5 0.65
0.60 0.225 0.138 0.38 0.23 4/200 *11 100 1.05 20 15.0 0.94 0.62
0.230 0.142 0.37 0.23 1/200 12 100 1.05 20 10.0 0.92 0.60 0.195
0.138 0.33 0.23 0/200 13 100 1.05 20 7.5 0.82 0.60 0.175 0.140 0.29
0.23 0/200 *14 100 1.05 20 5.0 0.78 0.58 0.163 0.142 0.28 0.24
2/200 *15 120 1.05 20 7.5 0.80 0.61 0.210 0.165 0.34 0.27 1/200 16
100 1.05 50 10.0 0.87 0.58 0.200 0.142 0.34 0.24 0/200 17 100 1.05
50 7.5 0.81 0.58 0.183 0.140 0.32 0.24 0/200 *18 100 1.05 50 5.0
0.74 0.56 0.178 0.139 0.32 0.25 1/200 *19 120 1.05 50 7.5 0.81 0.59
0.205 0.155 0.35 0.26 1/200 *20 100 0.95 20 15.0 0.95 0.57 0.228
0.139 0.40 0.24 2/200 21 100 0.95 20 10.0 0.92 0.55 0.193 0.138
0.35 0.25 0/200 22 100 0.95 20 7.5 0.84 0.54 0.180 0.136 0.33 0.25
0/200 *23 100 0.95 20 5.0 0.77 0.52 0.158 0.130 0.30 0.25 3/200 *24
120 0.95 20 7.5 0.81 0.53 0.205 0.160 0.39 0.30 2/200 *25 100 0.95
50 15.0 0.93 0.58 0.208 0.138 0.36 0.24 2/200 26 100 0.95 50 10.0
0.84 0.56 0.191 0.140 0.34 0.25 0/200 27 100 0.95 50 7.5 0.80 0.56
0.170 0.141 0.30 0.25 0/200 *28 100 0.95 50 5.0 0.72 0.53 0.160
0.132 0.30 0.25 3/200 *29 120 0.95 50 7.5 0.81 0.58 0.200 0.163
0.34 0.28 4/200
[0095] As seen in Table 2, as the continuity (B/A) of the inner
electrode layer is increased to 0.8 or more, the accelerated
lifespan is increased and reliability is improved.
[0096] In addition, it could be seen that the accelerated lifespan
is increased and reliability is improved when the continuity of the
inner electrode layer is 0.8 or more and the ratio (De/td) of the
average diameter of the contact dielectric grains to the average
thickness of the dielectric layers 1 is 0.35 or less.
[0097] Furthermore, it could be seen that the accelerated lifespan
is increased and reliability is improved when the continuity (B/A)
of the inner electrode layer is 0.8 or more, the ratio (De/td) of
the average diameter of the contact dielectric grains to the
average thickness of the dielectric layers 1 is 0.35 or less, and
the ratio (Dc/td) of the average diameter of the non-contact
dielectric grains to the average thickness of the dielectric layers
1 is 0.25 or less.
[0098] As set forth above, according to embodiments of the present
invention, a large-capacity multilayer ceramic electronic component
is manufactured to have improved continuity of the inner electrode
layer, large capacitance, extended accelerated lifespan and
excellent reliability due to an average diameter of dielectric
grains being controlled.
[0099] While the present invention has been shown and described in
connection with the embodiments, it will be apparent to those
skilled in the art that modifications and variations can be made
without departing from the spirit and scope of the invention as
defined by the appended claims.
* * * * *